The internal combustion engine is the primary power source for motorized vehicles throughout the world today. It is a well known and long used technology, and has become favored because it provides vehicles with both substantial power and good range, using a readily available fuel. Unfortunately, there are drawbacks to the internal combustion engine (xe2x80x9cICExe2x80x9d). The primary drawback of the ICE is pollution, since the combustion of petroleum-based fuels causes the emission of pollutants into the atmosphere. More recently, as fossil fuels have become more difficult to obtain and their costs have increased, concerns have also arisen regarding the availability of fuel (and thus the continued viability of ICEs) in the long term and the costs of operating ICEs in the short term. As a result, fuel efficiency in vehicles has become a significant issue, as demonstrated by both government-mandated efficiency guidelines and consumer-driven marketplace dynamics (as consumer demand has caused automobile manufacturers to stress the fuel efficiency of their vehicles in marketing). Automobile manufacturers have responded by constantly tweaking their internal combustion engines, attempting to find ways to maximize the gas milage of their vehicles to gain any sort of competitive advantage in this crucial area.
Since the basic design of the internal combustion engine is so well known and widely understood, most of the engineering design work attempting to improve fuel efficiency involves improvements to the peripheral elements of the ICE cycle, specifically the injection and compression elements. Automobile manufacturers have also worked with fuel producers to create better fuels, designed to burn both cleaner and more efficiently. These advances have significantly improved the fuel efficiency of modern vehicles, but concerns still remain. In an attempt to progress further, manufacturers have, at the prompting of government, begun exploring more radical options that have led them away from ICEs completely. Electric cars and hybrid vehicles represent the current trend for developing fuel efficient, clean, environmentally-friendly vehicles.
Unfortunately, these alternatives have practical problems of their own, which may prevent them from ever effectively replacing ICEs. Electric (battery powered) cars, for example, typically lack power/torque, such that they are ineffective for larger vehicles or for vehicles that pull significant weight (as cargo trucks, by way of example) and do not have an adequate range for anything more than short commutes. Hybrid vehicles are even more experimental at this point, and often rely upon unproven technology like hydrogen fuel cells. These sorts of hybrid vehicles have encountered many significant fuel-related setbacks that may prevent them from ever become practical, real-world vehicles.
The present invention of the Internal Combustion Engine Efficiency Unit (xe2x80x9cICEEUxe2x80x9d) takes a different tack. It provides a radically different approach to improving the fuel efficiency of internal combustion engines, so that vehicles can still enjoy the benefits of ICEs while gaining significant fuel savings by reconfiguring the specific manner in which their ICEs operate. This is accomplished using a technique which has heretofore been unavailable for internal combustion engines. Specifically, the ICEEU uses multiple (typically two) smaller engines in place of the single large engine that typically powers a motorized vehicle. The two smaller engines feed into the ICEEU, which produces a single rotational output from both engines to drive the vehicle (in the same manner that the vehicle would be driven by the single engine that has been replaced). Smaller ICEs are innately more fuel efficient, and the ICEEU allows one of the two engines to idle, cease operation, and/or resume operation while the vehicle is being driven, such that the vehicle can utilize both engines in tandem when power is needed (during acceleration for instance), but can run on only one engine (during cruising for instance) when much less power is needed to maintain the vehicle""s constant speed.
The primary benefit of the ICEEU is that it basically customizes the vehicle""s engine as a function of time, so that it provides the appropriate size of engine for the specific circumstances (instead of the current situation with ICEs, in which the engine size for a vehicle is selected one time at purchase to fit all circumstances, even though it may not be appropriate/efficient for much of the operation life of the vehicle). In other words, a vehicle""s weight-to-horsepower ratio can be optimized at all times, regardless of the vehicle""s speed, acceleration, or cargo weight, to best accomplish the goals at hand at the particular moment. This fact results in improved fuel efficiency. One way to increase fuel efficiency would be to have one engine run in its most efficient range of operation for basically its entire run cycle, while having the other engine provide additional power as needed. More typically, however, one ICE would be completely shut down and disconnected from the power train in circumstances when the additional power/torque is not needed, so that the pistons are not acting as a drag on the system, and the vehicle would then essentially behave as if it were driven by a single, smaller ICE (which is more fuel efficient).
In essence, the ICEEU would provide the vehicle with the power of a large engine when that power was needed (and the vehicle would act as if it had a single, large engine in those circumstances), but would provide the vehicle with the fuel efficiency of a smaller engine whenever there is no need for more power than a single, smaller engine produces (such that the vehicle would act as if it had a single, smaller engine in those circumstances). So by way of example, replacing a V-8 ICE with two 4 cylinder engines connected via the ICEEU would produce a vehicle that would act as an 8 cylinder engine in circumstances when power is needed (for instance, when accelerating quickly or when pulling a heavy load), but would act as a 4 cylinder engine in other circumstances (for instance, when cruising speed has been reached, and the vehicle is merely maintaining its forward momentum on the highway). In the dynamic situation between these two extremes, the vehicle would be able to use some portion of the second smaller engine""s power, as needed.
The present invention of the ICEEU allows engines running at different speeds to share the same load, and to enter and leave the power train as needed at any RPM or torque. It optimizes both the engines and the transmission of the vehicle so that a pair of engines can integrate and separate smoothly throughout operation (regardless of RPM or torque). Furthermore, the ICEEU allows internal combustion engines to be used in conjunction with other types of motors in the same manner (i.e. with the alternative motor replacing one of the smaller ICEs), so that it may be used to develop a hybrid vehicle. Regardless of the types of motors being integrated, the most significant point about the ICEEU is that it allows for the use of smaller, more efficient internal combustion engines, while maintaining high-end power availability, so that the vehicle""s weight-to-horsepower ratio remains appropriate at all times in the vehicle""s life.
At its heart, the present invention of the Internal Combustion Engine Efficiency Unit (xe2x80x9cICEEUxe2x80x9d) is an infinitely variable transmission device that features phase shifting as a means for translating two rotational inputs into a single rotational output. Basically, the ICEEU serves the functional purpose of synchronizing torque without synchronizing either rotational speed (RPMs) or horsepower. The ICEEU device could have several practical applications. For instance, it could be used to power a winch pulling fibreoptic cable, with the phase shifting nature of the device being exploited to allow cable to advance at a constant speed under a constant pull force. Or, it could be used to avoid the problem of having brushes weld to the armature of an electric motor, which is typically encountered when starting large DC motors from static position under extreme loads, by controlling motor speed increases using the dynamic counterbalancing effect of phase shifting to avoid the chance of flashover (by rotating one input clockwise and the other counterclockwise at the same speed to produce an infinite ratio, effectively producing no rotation in the output shaft, but allowing precise control over the output shaft rotation by slowing either motor, setting up an extreme ratio).
The primary use for the ICEEU, however, is to allow two separate internal combustion engines to work together as a single motivating force for a vehicle, optimizing both the engines and the transmission of the vehicle so that the pair of ICEs can integrate and separate smoothly at any RPM or torque. The ICEEU allows either of the engines to idle, cease operation, and/or resume operation, so that one of the vehicle""s engines may be taken in and out of the vehicle""s power train as needed. When one of the two engines is not in operation, it has no negative effect on the other engine and is not a source of friction or drag, which would reduce the efficiency of the power train. Thus, the ICEEU effectively allows a vehicle to act as if it has a larger engine when power is needed (by utilizing both engines as input power sources within the power train) and as if it has a smaller engine when there is no such need for power beyond the capabilities of a single smaller engine (by utilizing only one of its two smaller engines as an input power source for the power train of the vehicle). This effect results in a more fuel efficient, low-emission vehicle, which still has all of the advantages of internal combustion engines.
In basic form, the ICEEU comprises an open differential and two planetary gear sets, and each of the planetary gear sets connects to the open differential in a like manner (forming a mirror image). Typically, one planetary gear set is located on each side of the open differential. In the preferred embodiment, the open differential comprises an internal carrier, two side bevel gears, and planet (spider) bevel gears. Each planetary gear set comprises a sun gear, a plurality of planet gears and a planetary carrier (collectively forming a planetary array), and an annular gear. The appropriate side bevel gear on each side of the open differential rigidly connects to the annular gear for the planetary gear set located on that side of the open differential. The internal carrier for the open differential rigidly connects to the sun gears in both planetary gear sets and to the output shaft. The planetary array (specifically, the planetary carrier) for each planetary gear set connects to an input shaft from an ICE. In this way, the ICEEU connects two internal combustion engines together to produce a single rotational output, transmitting drive power for the vehicle.
To function most effectively as an engine efficiency unit, optional elements may be added to the ICEEU. For example, brakes may be added, so that elements of the planetary gear sets may be stopped, providing another rotational input that can alter the manner in which the ICEEU translates the two rotational inputs into a single rotational output. Clutch mechanisms may also be added to improve the device""s operation. For example, a one-way clutch may be used on one of the input shafts so that the speed of the engine attached to that shaft may be regulated with respect to the speed of the other engine (i.e. so that one input shaft is restricted so that it cannot rotate faster than the other input shaft). On the other hand, friction clutches could be used to allow each engine to easily engage and disengage from the power train. Also, there are several different means and locations at which the engines could be attached to the ICEEU. All of these factors will be discussed in greater detail below, when describing the preferred embodiment.
It is an object of the ICEEU to increase the fuel efficiency of internal combustion engines. It is another object of this invention to allow the weight-to-horsepower ratio for a vehicle to be customized depending upon the specific circumstances, so that it is appropriate regardless of the vehicle""s speed, acceleration, or cargo weight. It is still another object of this invention to integrate and separate two engines smoothly throughout the operation of a vehicle as needed, in order to optimize the performance characteristics of the vehicle. It is yet another object of this invention to allow two engines running at different speeds to share the same load. It is yet another object of this invention to allow the engines of a vehicle to enter and leave the power train as needed at any RPM or torque. These and other objects will be readily apparent to those skilled in the art field.